To attach a terminal to an end of an insulated wire, there is conventionally often used a crimping technique. The crimping is performed by caulking a conductor barrel formed in advance on the terminal to the end of a conductor of the insulated wire by use of a die.
This crimping technique, however, involves a difficulty of setting a crimp height of the conductor barrel. A low crimp height has a merit of lowering contact resistance between the conductor barrel and the conductor, while causing a demerit of decreasing mechanical strength, in particular tensile strength against an impact load (more specifically, the strength by which the crimp terminal holds the wire), because of a high reduction rate of the conductor sectional area. On contrary, a high crimp height has a merit of maintaining high mechanical strength while raising the contact resistance between the conductor barrel and the conductor of the wire.
Particularly in recent years, there is conducted a study on the use of aluminum or aluminum alloy as the material of the conductor included in the wire, the use of these materials involving extremely difficulty of setting the crimp height. Specifically, a surface of the aluminum or aluminum alloy tends to be formed with an oxide film which causes a deterioration in contact resistance; there is required setting a low crimp height low in order to lower a contact resistance sufficiently in spite of the formed oxide film. This means that it is not easy to set and manage the crimp height of a terminal-provided wire including a conductor made of aluminum or an aluminum alloy so as to satisfy both of mechanical strength and contact resistance requirements.
For this purpose, Patent Document 1 discloses a technique of forming simultaneously a high crimp height part and a low crimp height part in a conductor barrel. The high crimp height part is formed on a tip end side part of the conductor to contribute to mechanical strength maintenance, while the low crimp height part contributes to a lowered contact resistance.
The terminal-provided wire described in Patent Document 1, however, involves an existence of a discontinuous step between the high crimp height part and the low crimp height part of the terminal. The larger the step, the more likely damage such as cracks is given to the terminal. Furthermore, it is practically difficult to manufacture a terminal-provided wire including such a large step by use of a single crimping die; in actuality, separate crimping dies must be used for the different crimp height parts, management of which involves extreme troublesome.    Patent Document 1: Japanese Patent Application Publication No. 2005-50736